I have a single CUCM 9.1.2 server and a single Unity Connection 9.1.2 Server at my main office (no cluster). We are opening a branch office in another state and I need a solution for phones in that new office. I am thinking about using SRST. I would just get a 2900 series router with a SRST license for this branch office. All phones at the branch office would be registered to my CUCM at the Main Office, but if the main office went down, the phones at the remote site would stay up, and they could still make phone calls. Here's my question - Let's say my main office went complete down, whole building is without power, so my CUCM, Unity Connection, and voice gateway router are down, and someone calls our main number 777-777-7777, how could it be configured so now all calls going to 777-777-7777 are answered at the branch office?